Some Foci have the foglight pigtails already. Look behind your lower grille to see if there is any extra wiring hanging there, then all you would need is the headlight switch, grille for fogs and fogs.
If you don't want to buy that $89 ebay kit and would rather try to piece it together yourself for cheaper look here:
How To Make Your Own Wiring Harness For Fog Lights
Although, I don't think you can piece it together for cheaper than $89. That eBay kit is a good deal!